The present invention relates to vacuum cleaners. More particularly, the present invention relates to upright vacuum cleaners used for suctioning dirt and debris from carpets and floors.
Upright vacuum cleaners are ubiquitous. They are known to include an upper portion having a handle, by which an operator of the vacuum cleaner may grasp and maneuver the cleaner, and a lower cleaning nozzle portion which travels across a floor, carpet, or other surface being cleaned. The upper portion is often formed as a rigid plastic housing which encloses a dirt and dust collecting filter bag, although the upper portion may simply be an elongated handle with the filter bag, and an external cloth bag enclosing it, hung therefrom. The cleaning nozzle is hingedly connected to the upper handle portion such that the upper portion is pivotable between a generally vertical upright storage position and an inclined operative position. The underside of the nozzle includes a suction opening formed therein which is in fluid communication with the filter bag.
A vacuum or suction source such as a motor and fan assembly is enclosed either within the nozzle portion or the upper portion of the cleaner. The vacuum source generates the suction required to pull dirt from the carpet or floor being vacuumed through the suction opening and into the filter bag. A rotating brush assembly is typically provided in proximity with the suction opening to loosen dirt and debris from the surface being vacuumed.
To avoid the need for vacuum filter bags, and the associated expense and inconvenience of replacing the bag, another type of upright vacuum cleaner utilizes cyclonic airflow, rather than a filter bag, to separate a majority of the dirt and other particulates from the suction airstream. In some types of cyclonic vacuum cleaners, the air flows through a filter to remove residual particulates, before it flows to the motor. Some non-cyclonic upright vacuum cleaners also employ a filter and a dust cup.
Such prior art upright vacuum cleaners have not been found to be entirely effective and convenient to use. For example, with these prior art vacuum cleaners, the process of emptying dust and dirt from the dirt collection container has been found to be inconvenient, and often resulted in the spillage of the cup contents. Likewise, with these prior units, replacement of the filter element has not been convenient. Further, other prior art vacuum cleaners have been found to exhaust air which is not free of residual contaminants. For example, one prior unit filters the airstream after it passes through the cyclonic chamber, but thereafter passes the airstream through the motor assembly where it is potentially recontaminated by the motor assembly, itself, prior to its being exhausted into the atmosphere.
Because a single stage dust separation action of such vacuum cleaners does not completely remove all dust, dirt, and other contaminants from the suction airstream, it has been found desirable to include a filter downstream from the dust separation chamber. As such, prior art vacuum cleaners have heretofore employed cylindrical or planar filter elements including conventional media to filter the airstream after it passes through the dust separation chamber. These prior art filter elements are not optimum for all environments. Thus, a need has been found for a bagless vacuum cleaner with an effective filter positioned downstream relative to a dust separation chamber for effectively filtering the airstream without clogging.
Further, there is a need for a bagless vacuum cleaner that is readily usable for on-floor cleaning and above-floor cleaning. It would be additionally desirable for such a vacuum cleaner to be relatively simple and/or relatively inexpensive to manufacture and assemble. Accordingly, it has been deemed desirable to develop a new and improved upright vacuum cleaner which would overcome the foregoing difficulties and others while providing better and more advantageous overall results.